How Does Inertia Affect the Feel of Cycling?

[mistry]

Hi everyone, happy christmas

I am working on a project looking into the inertial feel of a bicycle. The overall aim is to calculate the inertia of a bike and rider and to consider how this inertia feel can be recreated in an exercise bike and to quantify the differences through testing. In order to do this I need to caluclate the inertia/momentum of a real bike and caluclate the inertia/momentum of a cycling ergometer. (I am not really sure what the difference is between inertia and momentum in terms of cycling and how it relates to feel)

The thing I am unsure about is what is the inertia, (is it a quantity or is it something that a cyclist feels) and how can it be calclated? Do I need to calculate inertia and momentum for example and how do I combine them. My intial thoughts are:
Frame and cyclist (momentum = mass x velocity)
Rotating wheel and crank (disc) (inertia =(mass x (radius)2)/2

The other issue is that I need to work out the inertia feel of a cycling ergoemter. Knowing that they have large mass fly wheels can I treat this as a disc and calcualte inertia in the same way and compare it to the above?

Thanks for you help in advance, it is much appreciated

Mistry

 

[eljose79]

Hello Mistry,

Thank you for sharing your project with us. It sounds like a fascinating topic to explore and I am happy to provide some guidance.

Inertia and momentum are closely related concepts, but they are not the same thing. Inertia is the resistance of an object to changes in its state of motion, while momentum is a measure of an object's motion. In the context of cycling, inertia can be thought of as the feeling of momentum that a cyclist experiences when pedaling and turning on a bike.

To calculate the inertia of a bike and rider, you will need to consider the combined mass and distribution of weight throughout the bike and rider. This can be done by calculating the individual inertia of each component (e.g. frame, wheels, pedals) and then combining them using the parallel axis theorem. This calculation will give you the total inertia of the bike and rider system.

When it comes to an exercise bike, the same principles apply. The large mass flywheel can be treated as a disc and its inertia can be calculated in the same way as the rotating wheel and crank of a regular bike. However, the distribution of weight and design of an exercise bike may be different from a regular bike, so it is important to take these factors into account when calculating the overall inertia.

I hope this helps to clarify the concepts of inertia and momentum in relation to cycling and your project. Best of luck with your research and happy holidays to you too!

 

[astrokreng]

Hello Mistry,

To answer your first question, inertia is a property of matter that describes its resistance to change in motion. In the context of cycling, it refers to the bike and rider's resistance to changes in speed or direction. Momentum, on the other hand, is a measure of the amount of motion that an object has. It is calculated by multiplying the mass of the object by its velocity.

In terms of calculating the inertia of a bike and rider, you can use the equation you mentioned: momentum = mass x velocity. This will give you a general idea of the inertia of the bike and rider as a whole. However, to get a more accurate calculation, you may want to break it down into different components such as the frame, wheels, and rider's body.

For the rotating wheel and crank, the equation you mentioned for inertia is correct. However, you may also want to consider the moment of inertia, which takes into account the distribution of mass around the axis of rotation.

When it comes to calculating the inertia feel of a cycling ergometer, you can treat the flywheel as a disc and use the same equation as the rotating wheel and crank. However, keep in mind that there may be other factors at play, such as the resistance settings on the ergometer, that can affect the inertia feel.

I hope this helps clarify the concepts of inertia and momentum in cycling and how they can be calculated. Best of luck with your project!